java - MapReduce 项目的 Mapper 部分中的多个错误
问题描述
我是一个非常新手的程序员,项目合作伙伴不会编码,需要今晚到期的学校项目的帮助(已经工作了一个多星期)。我正在尝试查找包含“Fortnite”一词并拥有超过 10000 个赞的视频的所有描述(来自 https://www.kaggle.com/datasnaek/youtube-new的 YouTube 数据)。我正在从 CSV 文件访问数据,我在代码的 Mapper 部分中遇到了多个错误,并且在我解决它之前无法进一步移动。这是我的第一个 Java/MapReduce/Hadoop 项目,我只是不明白我做错了什么。
在 Windows 10 64 位上运行 Java 1.8 和 Eclipse IDE 2019-03。我的两台电脑都有同样的问题,所以我很确定这是用户错误。我已经做了一个多星期了,我无法弄清楚。
Clean code:
package mapreduce,project;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.fs.Path;
public class project extends Mapper<LongWritable, Text, Text,
IntWritable>
{
public Text description = new Text();
private IntWritable likes = new IntWritable();
@Override
public void map(LongWritable key, Text value, Context context)
throws IOException, InterruptedException{
String line = value.toString();
String str[] = line.split("\t");
if(str.length >= 9){
description.set(str[8]);
}
likes = Integer.parseInt(str[8]);
if (likes >= 10000) {
context.write("Fornite", count);
}
} else {
return;
StringTokenizer itr = new StringTokenizer(line);
while(itr.hasMoreTokens()){
String token = itr.nextToken();
if(token.contains("Fortnite")){
word.set("Fortnite Count");
context.write(word, new IntWritable(1));
}
}
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Code with Errors:
package mapreduce.project;
----> (Error: Main method not found in class
mapreduce.project.project, please define the main method as:
public static void main(String[] args)
public class project extends Mapper<LongWritable, Text, Text,
IntWritable>
{
public Text description = new Text();
private IntWritable likes = new IntWritable();
@Override
public void map(LongWritable key, Text value, Context context)
-----> (ERROR: This sorce attachment does not contain the source for
the file Mapper.class. Change Attached Source....)
throws IOException, InterruptedException{
String line = value.toString();
String str[] = line.split("\t");
if(str.length >= 9){
description.set(str[8]);
}
likes = Integer.parseInt(str[8]); ----> ( ERROR: Type mismatch:
cannot convert from int to INTWritable)
if (likes >= 10000) { ----->(ERROR: the operator >= is undefined for
the argument type(0) IntWriteable, int)
context.write("Fornite", count); (ERROR------> count cannot be
resolved to a variable)
}
} else { ----->syntax error on "else" delete this token)
return;
StringTokenizer itr = new StringTokenizer(line);
while(itr.hasMoreTokens()){
String token = itr.nextToken();
if(token.contains("Fortnite")){
word.set("Fortnite Count");
context.write(word, new IntWritable(1));
}
}
Running the YouTube data through the MapReduce program, we expect to
obtain a list of YouTube videos that mention Fortnite in the description
have over 10,000 views.